This European Standard describes the specific functional requirements for steel pipelines in addition to the general functional requirements of EN 12007-1 for maximum operating pressures up to and including 16 bar. This European Standard specifies common basic principles for gas supply systems. Users of this European Standard should be aware that more detailed national standards and/or codes of practice can exist in the CEN member countries. This European Standard specifies common basic principles for gas infrastructure. Users of this standard should be aware that more detailed national standards and/or codes of practice may exist in the CEN member countries. This European Standard is intended to be applied in association with these national standards and/or codes of practice setting out the above mentioned basic principles. In the event of conflicts in terms of more restrictive requirements in national legislation/regulation with the requirements of this standard, national legislation/regulation takes precedence as illustrated in CEN/TR 13737 (all parts). CEN/TR 13737 (all parts) gives: clarification of all legislation/regulations applicable in a member state; if appropriate, more restrictive national requirements; a national contact point for the latest information.